Saint-Gobain Vetrotex: Glass Strand

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	Manufacturing
	The origins
	Forming
	Sizing
	Characteristics
	Glass filament identification
	The advantages
	The advantages of the composites reinforced with glass strands





Continuous filament mat	Chopped strands	Direct roving	Cake


	Glass tissues	Woven roving	Yarns

			Chopped strands mat

			Multi-ends roving

The manufacture of glass is carried out in a special furnace at around 1550°C (E glass) using finely ground raw materials from carefully selected quarries.
The glass leaving the furnace at a very high temperature is used to feed bushings (blocks pierced with hundreds of holes) of platinum alloy.
The majority of Saint-Gobain Vetrotex products are based on E glass. Other glasses are also used, for example R glass (high mechanical performance), D glass (high dielectric performance), AR glass (Alkali and corrosion resistant glass).



	Soon after the Egyptians mastered the manufacture of glass, resistant to wear through the centuries but fragile as a whole, they discovered the virtues of glass fiber, strong enough to "reinforce" the vases and amphorae found in the tombs of the Pharaohs. A product of human intelligence, the first artificial filament was born. Tiberius and the Roman Empire, Murano and the Italian Renaissance, Réaumur and the Siècle des Lumières, then Napoleon and the pre-industrial era: from one age to another, glass strand has spanned the millennia, to occupy its rightful place at last in our high-tech century. Thanks to the Saint-Gobain group of companies - heir of the famous Manufacture Royale des Glaces created by Colbert in 1665 and carrying on three centuries of glass-making tradition - Europe began to set up its own production facilities in 1938.



	The basic strand is made by forming. Forming is achieved by drawing the molten glass flowing from the holes of the bushing at high speed. This forms between 50 and several thousand filaments. These filaments are defined by their diameters: from 5 to 24 microns (1µm = 1/1000 mm).



	The individual filaments of Saint-Gobain Vetrotex reinforcements receive a coating of size at the forming stage, immediately after they leave the bushing. This size, made up of organic products dispersed in water, is designed to give the glass strand certain characteristics necessary for final processing. Each size is specially designed for a molding or compounding process and for a different matrix type. It usually contains a silane type chemical "coupling agent" which contributes to enhancing the mechanical properties of composites and particularly their resistance to aging. Saint-Gobain Vetrotex products are either manufactured immediately after they leave the bushing (direct roving, Unifilo continuous filament mat, chopped strands) or made up of basic strands subjected to finishing operations which are complicated to a greater or lesser degree (cabling for yarns, assembly for rovings, chopping of chopped strands, chopping and forming of chopped strand mats).